Mass spectrometry has proved to be the most powerful method of identifying and quantitating a number of extremely important neuroregulators and their metabolites. The neuroregulators are substances which act as transmitters between nerve cells (neurotransmitters) or as modulators of neuronal function (neurodmodulators). We have made extensive use of computer assisted gas-liquid chromatography/mass spectrometry in our clinical studies of depression and schizophrenia as well as for behavioral and pharmacological investigations in animals utilizing perfusion techniques or brain tissue. Recent developments in the instrumentation including changes in the system design, addition of chemical ionization sources, and the determination of negative ions as well as positive ions, have resulted in increases in sensitivity of 5 to 10 fold in the traditional electron impact source mode to 10 to 100 fold with chemical ionization and negative ion mode of operation. Because our work is continually dealing at the limits of sensitivity and because of the intense need for such increased performance we are requesting a supplement to our on-going program-project grant to pay a portion of the cost of obtaining such improved instrumentation.